Spherical rod ends provide an articulated linkage between the connection of two separate assemblies. Spherical rod ends can be easily adapted for many different types of applications. In use, the spherical rod end enables the linkage of two separate assemblies, such that the linkage is articulated between the two separate assemblies. The articulation of the linkage is provided through the spherical ball of the spherical rod end. In use, the spherical ball engages a first separate assembly, while an elongated cylindrical member of the spherical rod end engages a second separate assembly. Thus, the spherical rod end operates to articulately link two separate assemblies.
The prior art spherical rod end comprises a metallic housing and a metallic ball. The metallic ball is provided with a central hole for engaging a separate assembly. The metallic housing is molded to form a spherical race around the metallic ball such that the metallic ball is generally able to move freely within the metallic housing. The metallic housing also forms an elongated cylindrical member. The prior art metallic spherical rod end quite often was able to sufficiently support loads in excess of one thousand pounds.
The prior art spherical rod end possesses distinct disadvantages. Since the prior art spherical rod end is constructed entirely of a metallic substance, it is prone to be heavy and is expensive to manufacture as it requires a protective, non-corrosive secondary finishing to avoid the effects of oxidation and corrosion. Additionally, quite often the spherical ball requires lubrication in order to maintain its free movement within the race of the metallic housing. Secondly, when both the spherical ball and housing are fitted together, the metallic embodiments of the ball and housing produce a loose tolerance with a high wear factor between the spherical ball and metallic housing. Further, since the metallic housing is directly molded around the metallic ball, quite often this tends to fuse the ball to the housing inhibiting the spherical ball's ability to move freely, therein requiring an additional manufacturing process to free the ball from the metallic housing. Furthermore, if the metallic ball is not perfectly round, the ball typically will be locked into place in the housing, devoid of any movement. Still further, in order to provide the elongated cylindrical member with a threaded portion, the threading of the elongated cylindrical member has to be formed either through a secondary process or through the molding process, requiring still another additional monetary expense. In conclusion, the prior art spherical rod end has numerous setbacks, and any attempt to overcome any of these setbacks, had to be performed at a considerable monetary expense.
An example of a metallic spherical rod end is manufactured by Superior Linkage Products of New Haven, Indiana. The Superior Linkage device included a metallic ball and a metallic housing, both of which are plated for corrosion resistance. Additionally, the metal used for both the ball and housing is of a low carbon steel having the surface hardened for wear resistance. The Superior Linkage Products device is further provided with a bearing raceway constructed of a self-lubricating, reinforced nylon. In the process of manufacturing the Superior Linkage Products spherical rod end, first a metallic ball is formed with a central hole. The metallic housing is then molded to form a metallic raceway around the metal ball, with a cylindrical member extending away from the metallic raceway. Next, a self-lubricating, reinforced nylon is injected into the metallic raceway to provide for a bearing raceway. The cylindrical member may or may not be formed with an outer circumferential surface and/or an inner circumferential surface. However, even though the Superior Linkage Products spherical rod end is able to overcome some of the shortcomings of the prior art, the Superior Linkage Products device is expensive to manufacture. Additionally, the Superior Linkage Products device is primarily constructed of a metallic substance, and thus it is heavy.
An attempt has been made in the prior art to manufacture an all-plastic rod end. Adams et al. U.S. Pat. No. 5,129,148 teaches of a method for making a non-metallic, fiber reinforced rod end bearing assembly. This method provides an all-plastic rod end comprising; two discrete races, a spherical ball and a housing cover. The two races operate to support the spherical ball while they are in face-to-face alignment with one another. The two race members threadingly engage the housing, therein providing a means to gain access to the spherical ball while it is contained in the rod end. However, since the two races members are only threadingly engaged with the housing, and are not encased by the housing, this makes the Adams et al. rod end particularly the threaded engagement portion of the race members and housing, susceptible to fatigue and breakage when in use for a prolonged period of time.
Accordingly, it is an object of the subject invention to provide a new and improved spherical rod end without the shortcomings as forementioned.
Another object of the subject invention is to provide a new and improved spherical rod end which is constructed entirely of a lightweight material, such as plastic.
An additional object of the subject invention is to provide a new and improved spherical rod end which is constructed entirely of a corrosion resistant material.
Still a further object of the subject invention is to provide a spherical rod end which can be easily manufactured for various types of applications.
It is another object of the subject invention to provide a new and improved process for manufacturing a spherical rod end that enables a spherical rod end to be formed at a reasonable cost, and which is capable of linking separate assemblies, with an articulated linkage between the two separate assemblies.